Field of the Invention
The present invention relates to a fixed-focus imaging lens that forms an optical image of a subject on an image sensor, such as, for example, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), and an imaging device equipped with the imaging lens and performs imaging, such as a digital still camera, a camera equipped portable phone, a personal digital assistance (PDA), a smartphone, a tablet terminal, a portable game machine, or the like.
Description of the Related Art
Along with a widespread use of personal computers in homes, digital still cameras that can input image information, such as imaged landscapes and portraits, in personal computers are spreading rapidly. In addition, more and more portable phones, smartphones, and tablet terminals are equipped with camera modules for image input. Such devices having imaging capabilities use image sensors, such as CCDs, CMOSs, and the like. Recently, as downsizing of these image sensors have advanced, imaging devices as a whole and imaging lenses equipped therein are also demanded to be downsized. At the same time, higher pixel count of image sensors is also in progress, and high resolution and high performance are demanded for imaging lenses. For example, a performance compatible with 5 mega pixels or greater, more preferably, 8 mega pixels or greater is demanded.
In order to meet such demands, an imaging lens composed of a relatively large number of lenses, i.e., five lenses, is proposed, and recently an imaging lens composed of six lenses has also been proposed. For example, Taiwanese Patent Publication No. 201305595 and Korean Patent Publication No. 2010-0040357 propose six-element imaging lenses, composed of a first lens having a positive power, a second lens having a negative power, a third lens having a positive power, a fourth lens having a positive power, a fifth lens having a negative power, and a sixth lens having a negative power are disposed from the object side.